Test Details: Acute Myelogenous Leukaemia/Myelodysplastic syndrome is a group of heterogeneous hematologic conditions with characteristic chromosome abnormalities leading to specific gene rearrangements. Fluorescence in situ hybridization (FISH) is a sensitive method to detect smaller genomic changes associated with various haematological malignancies and solid tumours. Chromosomal abnormalities correlate with the prognosis and therapy. Currently, cytogenetic results allow stratification of patients with AML into 3 classes favourable, intermediate and unfavourable, according to clinical prognosis that is reported in literature. So, patients with t(8;21)(q22;q22) [RUNX1/RUNX1T1] have favourable prognosis with good response to treatment and complete remissions. FISH studies are useful adjuncts to complete chromosomal studies.